Revenue - Narrative (Details) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Contract assets	$ 0	$ 0
Deferred revenue	29,243,000	23,760,000
Courses in Progress
Disaggregation of Revenue [Line Items]
Future revenue	18,000,000	13,000,000
Future Courses
Disaggregation of Revenue [Line Items]
Future revenue	$ 11,200,000	$ 10,800,000